FINE-SCALE OSCILLATORY BANDING IN OTOLITHS FROM ARCTIC CKIARR (SALVELINUS ALPINUS) AND PIKE (ESOX LUCIUS)

摘要

Transmission electron microscopy of eoliths from the inner ear of arctic char and pike has revealed the presence of fine banding on the scale of several nanometers. The thickness of the bands was observed to vary in different portions of the sample, and some areas were not banded. ED’s analysis could not detect chemical differences within the bands, but electron diffraction showed that the crystallographic orientation of the bands is related by a lattice mismatch. Previously, banding on the scale of 50 to 100 microns was observed by SEM in eoliths from arctic char and was attributed to seasonal variations in growth. The fine-scale banding observed in this study, however, is unlikely to represent a daily variation. Electron diffraction from the pike samples shows that the material is composed of CaC03 having the both the valerate and aragonite structure, and hydrous CaC03 was also observed. The large-scale banding previously identified by SEM was not observed in the TEM despite attempts to intersect the boundaries of the micron-sized layers.